i to CORAL-REEFS. 



• 

 Laccadive group) which has an average depth between 

 25 and 35 fathoms, but that on some other banks in 

 the same group with only ten or twelve fathoms water on 

 them (for instance, the Tillacapeni bank), the coral was 

 living. 



With regard to the coral-reefs in the Red Sea, Ehrenberg 

 has the following passage : — " The living corals do not 

 descend there into great depths. On the edges of islets 

 and near reefs, where the depth was small, very many 

 lived; but we found no more even at six fathoms. The 

 pearl-fishers at Yemen and Massaua asserted that there was 

 no coral near the pearl-banks at nine fathoms deep, but 

 only sand. We were not able to institute any more special 

 researches." 1 I am, however, assured both by Captain 

 Moresby and Lieut. Wellstead, that in the more northern 

 parts of the Red Sea, there are extensive beds of living 

 coral at a depth of 25 fathoms, in which the anchors of 

 their vessels were frequently entangled. Captain Moresby 

 attributes the less depth, at which the corals are able to 

 live in the places mentioned by Ehrenberg, to the greater 

 quantity of sediment there ; and the situations, where they 

 were flourishing at the depth of 25 fathoms, were protected, 

 and the water was extraordinarily limpid. On the leeward 

 side of Mauritius, where I found the coral growing at a 

 somewhat greater depth than at Keeling atoll, the sea, owing 

 apparently to its tranquil state, was likewise very clear. 

 Within the lagoons of some of the Marshall atolls, where the 

 water can be but little agitated, there are, according to 

 Kotzebue, living beds of coral in 25 fathoms. From these 

 facts, and considering the manner in which the beds of 

 clean coral off Mauritius, Keeling Island, the Maldiva and 



1 Ehrenberg, Uber die Natur, etc., p. 50. 



